Buggy code:
public class ClasspathEntry implements IClasspathEntry { public static final String TAG_CLASSPATH = "classpath" ; public static final String TAG_CLASSPATHENTRY = "classpathentry" ; public static final String TAG_OUTPUT = "output" ; public static final String TAG_KIND = "kind" ; public static final String TAG_PATH = "path" ; public static final String TAG_SOURCEPATH = "sourcepath" ; public static final String TAG_ROOTPATH = "rootpath" ; public static final String TAG_EXPORTED = "exported" ; public static final String TAG_INCLUDING = "including" ; public static final String TAG_EXCLUDING = "excluding" ; public int entryKind ; public int contentKind ; public IPath path ; private IPath [ ] inclusionPatterns ; private char [ ] [ ] fullInclusionPatternChars ; private IPath [ ] exclusionPatterns ; private char [ ] [ ] fullExclusionPatternChars ; private static final char [ ] [ ] UNINIT_PATTERNS = new char [ ] [ ] { "Non-initialized<seq2seq4repair_space>yet" . toCharArray ( ) } ; private String rootID ; private AccessRestriction importRestriction ; private static final AccessRestriction UNINIT_RESTRICTION = new AccessRestriction ( null , null , null , null ) ; public static final IPath [ ] INCLUDE_ALL = new IPath [ ] { } ; public static final IPath [ ] EXCLUDE_NONE = new IPath [ ] { } ; public IPath sourceAttachmentPath ; public IPath sourceAttachmentRootPath ; public IPath specificOutputLocation ; public static final int K_OUTPUT = 10 ; public boolean isExported ; public ClasspathEntry ( int contentKind , int entryKind , IPath path , IPath [ ] inclusionPatterns , IPath [ ] exclusionPatterns , IPath sourceAttachmentPath , IPath sourceAttachmentRootPath , IPath specificOutputLocation , boolean isExported ) { } public ClasspathEntry combineWith ( IClasspathEntry referringEntry ) { if ( referringEntry == null ) return this ; if ( ( ( referringEntry . isExported ( ) ) || ( ( referringEntry . getInclusionPatterns ( ) . length ) > 0 ) ) || ( ( referringEntry . getExclusionPatterns ( ) . length ) > 0 ) ) { <START_BUG> return new ClasspathEntry ( this . getContentKind ( ) , this . getEntryKind ( ) , this . getPath ( ) , ClasspathEntry . concatPatterns ( referringEntry . getInclusionPatterns ( ) , this . getInclusionPatterns ( ) ) , ClasspathEntry . concatPatterns ( referringEntry . getExclusionPatterns ( ) , this . getExclusionPatterns ( ) ) , this . getOutputLocation ( ) , this . getSourceAttachmentPath ( ) , this . getSourceAttachmentRootPath ( ) , ( ( referringEntry . isExported ( ) ) || ( this . isExported ) ) ) ; <END_BUG> } return this ; } public static IPath [ ] concatPatterns ( IPath [ ] patternList1 , IPath [ ] patternList2 ) { } private static IPath [ ] decodePatterns ( Element element , String tag ) { } public char [ ] [ ] fullExclusionPatternChars ( ) { } public char [ ] [ ] fullInclusionPatternChars ( ) { } public void elementEncode ( XMLWriter writer , IPath projectPath , boolean indent , boolean newLine ) { } public static IClasspathEntry elementDecode ( Element element , IJavaProject project ) { } private static void encodePatterns ( IPath [ ] patterns , String tag , Map parameters ) { } public boolean equals ( Object object ) { } private static boolean equalPatterns ( IPath [ ] firstPatterns , IPath [ ] secondPatterns ) { } public int getContentKind ( ) { } public int getEntryKind ( ) { } public IPath [ ] getExclusionPatterns ( ) { } public IPath [ ] getInclusionPatterns ( ) { } public AccessRestriction getImportRestriction ( ) { } public static char [ ] [ ] getAccessRestrictionPatterns ( IPath [ ] patternSequence ) { } public IPath getOutputLocation ( ) { } public IPath getPath ( ) { } public IPath getSourceAttachmentPath ( ) { } public IPath getSourceAttachmentRootPath ( ) { } public int hashCode ( ) { } public boolean isExported ( ) { } static int kindFromString ( String kindStr ) { } static String kindToString ( int kind ) { } public String toString ( ) { } public String rootID ( ) { } public IClasspathEntry getResolvedEntry ( ) { } public static IJavaModelStatus validateClasspath ( IJavaProject javaProject , IClasspathEntry [ ] rawClasspath , IPath projectOutputLocation ) { } public static IJavaModelStatus validateClasspathEntry ( IJavaProject project , IClasspathEntry entry , boolean checkSourceAttachment , boolean recurseInContainers ) { } }

Fix:
return new ClasspathEntry ( this . getContentKind ( ) , this . getEntryKind ( ) , this . getPath ( ) , ClasspathEntry . concatPatterns ( referringEntry . getInclusionPatterns ( ) , this . getInclusionPatterns ( ) ) , ClasspathEntry . concatPatterns ( referringEntry . getExclusionPatterns ( ) , this . getExclusionPatterns ( ) ) , this . getSourceAttachmentPath ( ) , this . getSourceAttachmentRootPath ( ) , this . getOutputLocation ( ) , ( ( referringEntry . isExported ( ) ) || ( this . isExported ) ) ) ;